The invention pertains to portable ramps particularly suited for permitting wheeled devices such as hand trucks and the like to be easily drawn over a curb by a single man.
In the prior art it is well known to use ramps to bridge differences in height so that wheeled vehicles may be easily moved to or from a higher or lower location. Examples of such ramps are shown in the following United States Patents: U.S. Pat. No. 3,984,891, Oct. 12, 1976 to Weinmann for a portable ramp having pivoted ends for adjustment to varying bridged heights; U.S. Pat. No. 3,936,898, Feb. 10, 1976 to Poe for a folding wheelchair ramp with pivotable legs and a handle; U.S. Pat. No. 3,818,528, June 25, 1974 to Petersen for a portable folding wheelchair ramp; U.S. Pat. No. 2,760,216, Aug. 28, 1956 to Curtis for a portable ramp having wheels and height adjustment; U.S. Pat. No. 2,597,213, May 20, 1952 to Whiteman for a movable ramp having wheels; U.S. Pat. No. 1,821,734, Sept. 1, 1931 to Viche for a curved toe board with projections thereon for preventing slipping; and U.S. Pat. No. 1,210,133, Dec. 26, 1916 to Baker for a trucking skid having a hinged curved lower end for engaging the wheels of a hand truck or the like.
Curbs, steps, and similar height obstructions are common problems for delivery men and others, who must pull heavily loaded hand trucks over these obstructions daily. Back and other injuries are not uncommon as these person are called upon to pull hand trucks loaded with approximately 250 pounds of, for example beverages, over typical eight inch curbs many times a day in the course of their business. In addition to physical injury, a substantial amount of work time and money is lost by employers as a result.
The special problems of these delivery persons, employees of soft drink and beer distributors and the similarly situated, are special and are not met by the prior art. In particular, the prior art has not provided a light weight ramp which is compact, easily carried by a single person and formed to permit a heavy truck to be easily pulled onto the ramp, while the ramp is securely positioned against the curb or other obstruction.